Electrode



K. TORNBEl-RG.

v ELECTROBE.

APPLICATION FILED Auma. 19m.

Patented Maf. 23,1920.

` j f lnvetor Knut Tornberg His Attmeg';

rrnn srarns Mllllllhltll tllzlllttlltl il..

Specicaton of Letters Patent.

intenten tirar. aa, inno.

.application filed August mi, 19MB. Serial No. tlt.

liynn, in the county of Essex, State of lt'lassachusetts, have invented.V certain new and useful llmprovements in Electrodes, ot' which the following is a specification.

My invention has reference to improve` ments in negative electrodes used in connec tion with positive electrodes of copper or other metals or combinations of metals which are generally spoken ot' as noncon suining electrodes, u'hile the negatives 4are consumed at a rate depending on thetype used and strength ot current. The principal ingredient of the negative electrodes is an iron oxid, mainly the magnetic oxid ot iron called magnetite (Feth), and these electrodes are, therefore, known in the art as.

magnetite electrodes. Various admixtures are used uith the magnetite; some native or artilicial materials containing titanium and some containing chromium. l'he principal titanium bearing materials used either singly or in combination as admixtures to the magnetite are rutile, ilmenite and titanium carbid, and in addition to these are used minute quantities of `various fluxes, such, for example, either singly or in combination the fluorids of sodium, potassium, lithium, magnesium and calcium, as iyell as other compounds.

llt has been found that magnetite mixtures in Whichilmenite is used in place ot the more expensive rutile while Working successfully with such low current as 4 amperes exhibit one defect When operated with currents as high as 6.6 amperes, Which are carried on many arc lamp circuits. lWhen run at this higher current (6.6 amps.) these electrodes form at the arcing end a cap which does not securely fuse to the iron tube in which the. mixture is held; the caps become loose and by the operation of starting and vfeeding they are knocked oft, and have to be formed anen' so frequently that at this higher current these electrodes could not be commercially used.

Jltnother defectin 'which all magnetite electrodes share (Whether ot the rutile or ilmenite type) is the formation at the arcing end of a liquid pool. This is called paddling of the electrode and it gives rise to rotation ot the arc With consequent un steadiness of the light. -The usual means operated at the hi for overcoming paddling is the addition to the electrode mixture ot one or more ol the fluxes heretotore mentioned; but some ot these fluxes depress the candle power, some increase consumption, While some have other drawliacks, as tor example, that ot being expensive.

.By my inrention puddling is cured simply, cheaply and effectively, and by its use ilmenite becomes available in place ot rutile for magnetite electrodes and an be gher current.

'lhev invention consists in the application to the inner Wall of the iron electrode tube ot a film of Water-glass, either the potassium or the sodium silicate.

The accompanying drawing slioivs in lfigure l, a longitudinal axial section of a magnetite electrode embodyingl my invention. and in Fig. 2 a like section of the upper part of a. modification thereof.

Referring to Fig. l, the electrode tube l, usually made of iron, is closed at the bottom by a thimble and the inner surface o'l the tube is lined with a film 3 of water-glass. This Water-glass may be either the silicate ol potassium or the silicate ot soda. or a mixture, of both. ,lilach of these ingredients, used alone, has proved to be quite effective tor the purposes ot my invention. rlhe [ihn may be applied by flooding the inner sur'lace of the tube with an aqueous solution of the Water-glass and allowing the same to drain and dry. Ot course, any other method olfproducing a thin coating` of Water-glass may be used.

The magnetite mixture @l is then filled into and compacted in the tube. is thenrtopped with a seal 6 about 11' thick, consisting of filling mixture made into a plastic mass by shellac solution and the tube is then closed. by a metal disk 5, as usual.

` This film of Water glass causes the cap formation to fuse securely to the iron shell ot' the electrode. lt also prevents puddling Withoutthe use ot fluxes, which heretofore hare been found necessary for this purpose. lt is the immediate contiguity ot the requisite amount of Water glass both to the magnetite mixture and to the iron shell that renders the fusion ot the cap formation to the shell a matter of certainty throughout the length of the electrode. A like certainty of the fusion of the cap to the shell cannot be attained. when the Water glass is made a i part of the fillingl mixture, no matter how uniformly it may be distributed throughout ceney mixtures, e'. e. magnette mixtures referred to above as being of the rutile type and containing titanium carbid besides the rutile, I have found it desirable, even though not absolutely necessary, to use a special seal immediately beneath the capping disk 5.

This is Vshown in Fig. 2, the special seal con` sisting of a layer 6 about thick, of filling mixture into which has been incorporated about one-half of one per cent. of anhydrous potassium fluorid, shellac solution being used as a binder, asin the case of the usual seal, mentioned above; the special seal thus becomes a solidified button.

. insurance against puddling to which these the special seal itself has been consumed.

lVhat I claim as new and desire to secure by Letters Patent of the United States, is 3 1. An electrode comprising a metal tube, a Hlm of water-glass on the -inner surface thereof, anda filling of a magnetite mixture in the tube. I

2. An electiode comprising a metal tube, a film of Water-glass on the inner surface tliereof,and a filling of ilmenite in the tube.

3. An electrode comprising a metal tube, a film of Water-glass on the inner surface thereof, a filling of a magnetite mixture in the tube, and a seal on top ofthe filling, consisting of a solidified button of plastic filling material, having about one-half o f one per l potassium fluorid 1ncor.

cent. of anhydrous porated therein. f

In Witness whereof, I have hereunto set i niy hand this 26th day of August, 1918. This special seal6 .a'ets as an additional KNUT TORNBERG'. 

